Optical fiber communication systems are lightwave systems employing optical fibers to transmit information from an optical transmitter to an optical receiver. An optical transmitter for an optical fiber communication system includes an optical source, such as a semiconductor laser, that generates an optical signal and an optical modulator that modulates the optical signal with electronic data, video or voice information.
The optical transmitter also includes all of the electronics and the optics necessary to process the electronic information and modulate it onto the optical signal. The modulated optical signal is transmitted through a transmission media, such as an optical fiber, to an optical receiver. The optical receiver detects the transmitted optical signal and processes the optical signal to generate an electronic waveform that contains the data, video or voice information.
Optical fiber communication systems are now widely deployed. Recently, relatively new communication services, such as the Internet, high-speed data links, video services, wireless services and CATV, have resulted in a dramatic increase in the need for higher information data rates. The aggregate data throughput rate of a communication system can be increased either by increasing the bandwidth of an individual data channel or by increasing the number of data channels.
Many optical fiber communication systems today are being built to transmit data over long distances with higher data rates or with a larger number of data channels. Moreover, in order to reduce the capital and operating costs associated with transmitting data, such systems are currently being built to transmit data, video and voice over these longer distances without employing repeaters.
To achieve these higher data rates and longer transmission distances, a large number of channels can be used. For example, state-of-the art CATV systems transmit greater than one hundred channels over a single communication link. To transmit such a large number of channels, while maintaining signal integrity over all of the channels, the optical transmitter should be substantially linear and free of distortion.